1. Field of the Invention
The present invention is generally directed to a solar tracker and more specifically to a modular support assembly for a solar tracker that allows reduced assembly and transportation costs.
2. Description of the Prior Art
Solar energy systems have a wide variety of variation depending upon the type of solar energy collected. Due to the rotation of the Earth, the tilted axis of the Earth, and the orbit path of the Earth around the sun, the position of the sun in the sky is ever changing. To maximize the amount of solar energy collected by a solar system, the solar collector, such as photovoltaic panels, reflectors, lenses and other optical devices are preferably mounted to a solar tracker which minimizes the angle of incident between the incoming light and the solar panel thereby maximizing the amount of energy produced.
Therefore, most solar energy systems use some form of a solar tracker which allows the solar collector to minimize the angle of incidents between the incoming light and the solar collectors, specifically by orienting the solar collector directly toward the position of the sun as it moves across the sky during the day, and adjusting each day to the different position of the sun in the sky caused by the tilt of the Earth's axis and its orbit relative to the sun. Therefore, the primary benefit of a tracking system is to collect solar energy for as long as possible each day and maximize accurate alignment as the sun's position shifts depending upon the season. A single axis tracker may increase the annual output of a solar collector by approximately 30% wherein a dual axis tracker which also may account for positioning of the sun due to the season may add an additional 6% of increased output. For flat panel solar collectors such as photovoltaic panels, the energy contributed by the direct beam of light from the sun drops off with the cosign of the angle between the incoming light and the panel. For concentrated photovoltaic trackers, the tracking accuracy requirements are even greater as the tracking accuracy must generally be approximately ±0.1° to deliver approximately 90% of the rated power output for high concentration systems and ±2.0° to deliver 90% of the rated power output in low concentration systems. Therefore, concentrated photovoltaic systems generally use a dual-axis solar trackers.
Misalignment of the support assembly during the manufacturing process may also cause a decrease in efficiency of the attached solar collector. More specifically, if the angles or placement of the supporting assembly and each component thereof are not precise, the efficiency of the solar panel is also reduced. This is particularly acute in concentrating photovoltaic systems where an accuracy of ±0.1° may significantly reduce the efficiency of the solar energy collected. Given the large dimensions of solar trackers, it is very difficult even under the best conditions in a manufacturing facility to obtain precise placement of the assembled parts which has also limited the ability of solar facilities to perform any on-site assembly of solar tracker support structures.
Most large scale solar array systems are typically located some distance away from population centers due to land cost or space constraints and more particularly are located significant distance away from most manufacturing facilities where solar trackers are formed. Given the remote location of most solar facilities, the transportation cost from the manufacturer's facility to the solar facility where it is installed may be significant. Currently, solar trackers are generally shipped with the complete support assemblies already assembled thereby requiring special trucks to handle the size and weight of the load, special oversized permits may be needed to transport the solar tracker from the manufacturing facility to the solar facility. Transportation costs also typically limit the ability of solar facilities to purchase from multiple manufacturing facilities as it is generally not cost-effective to ship the solar trackers over long distances. The requirement of proximity to manufacturing facilities has created a fragmented solar tracker manufacturing industry.
Therefore, there is a need for a solar tracker assembly that may be shipped cost-effectively over a long distance without the need for special oversized permits, be easily assembled, and have a high degree of accuracy when installed at the desired location.